Niveles de actividad física y gasto frente a pantallas en escolares: diferencias de edad y género / Levels of physical activity and time spending in front of screens in schoolchildren: differences in age and gender

Resumen Introducción: Cada vez se masifican las tecnologías electrónicas de pantalla entre la población infantil, práctica que ha llevado a un estilo de vida sedentario incrementa los riesgos para la salud de los individuos. Objetivo: Asociar la actividad física y el uso de pantallas, con el índice de masa corporal (IMC) y el género en escolares urbanos de la ciudad de Popayán entre 10 a 12 años. Materiales y métodos: Muestreo aleatorio simple, 440 escolares en edades entre los 10 y 12 años (220 niños/220 niñas). Se realizó la encuesta Physical activity Questionnaire for Older Children-PAQ-C. Estudio prospectivo transversal comparativo, de análisis univariado y bivariado. Resultados: Existe la asociación entre niveles de actividad física moderados y las horas de uso de pantallas (X2=598,6; p=0,00); así como también entre el nivel de actividad física y el sexo de los escolares (X2=13,551; p=0,004). Conclusiones: Los niveles de actividad física y el uso de pantallas demuestran que los escolares que usan con mayor frecuencia la televisión, el computador y los videojuegos, despliegan la actividad física en niveles de moderada a baja.

Abstract Introduction: Use of electronic screen technologies are increasingly widespread among children and their frequent use has led to a sedentary lifestyle that increases health risks in this population. Objective: To study the association of physical activity and the use of electronic screen devices with the body mass index (BMI) and gender in urban schoolchildren aged between 10 to 12 years from the city of Popayán (Cauca, Colombia). Materials and methods: A comparative prospective cross-sectional study, with univariate and bivariate analyses, was carried out using a simple random sampling of 440 students between the ages of 10 and 12 years (220 boys/220 girls). The Physical activity Questionnaire for Older Children (PAQ-C) was applied. Results: There is an association between moderate levels of physical activity and hours spent in front of electronic screen devices (X2=598.6; p=0.00). Likewise, an association between the level of physical activity and gender of schoolchildren was found (X2=13.551; p=0.004). Conclusions: Children who frequently use television, computers, and/or video games show low to moderate levels of physical activity.

Dual role of 2-tosylaminomethylaniline as a ligand and a nucleophile in the copper-mediated oxidation of methanol.

Some reactivity in the oxidation of methanol to formaldehyde has been spectroscopically detected on the methanolic mother liquors of a copper(ii) complex of a Schiff base ligand derived from the condensation of 8-hydroxyquinoline-2-carboxaldehyde and 2-tosylaminomethylaniline. An investigation has shown that 2-tosylaminomethylaniline (HA(TS)) plays a dual role in the oxidative process acting as a N-donor ligand and reacting in situ with formaldehyde, which leads to 3-tosyl-1,2,3,4-tetrahydroquinazoline (1). This was characterized by using both spectroscopic and X-ray diffraction techniques. The influence of 8-hydroxyquinoline derivatives, water and ligand stoichiometry on the yield of 1 was studied.

Encapsulation of atmospheric CO2 by a self-assembled decanuclear cadmium complex via unfamiliar perchlorato and carbonato bridges.

A decanuclear Cd complex has been found as a carbonate-containing capsule. The structure strongly resembles a ten-blade waterwheel with a central carbonate ligand surrounded by two superimposed Cd(5)O(5) crowns with a pentagonal antiprism-like disposition. The capsule is doubly capped by two pentadentate perchlorate anions.

Structural variety of zinc and copper complexes based on a 2,3-disubstituted 1,2,3,4-tetrahydroquinazoline ligand.

The ring-chain tautomerism of 2-(3-tosyl-1,2,3,4-tetrahydroquinazolin-2-yl)quinolin-8-ol (H(2)L(ring)) has been exploited to produce mononuclear complexes or, alternatively, dinuclear complexes, as desired, by varying the stoichiometry of the ligand. Cu(2+) and Zn(2+) stabilise the ring tautomeric form of the ligand in their mononuclear complexes M(HL(ring))(2). The structural characterisation of Zn(HL(ring))(2)·2MeOH·0.5H(2)O shows O,N-donor behaviour of the ring tautomer. The 1,2,3,4-tetrahydroquinazoline undergoes a ring-opening reaction upon formation of phenoxo-bridged dinuclear complexes M(2)(L(chain))(2) in which the chain tautomer is acting as O,N,N,N-donor. The crystal structure of Cu(2)(L(amide))(L(quinazoline))(MeOH)·2MeOH evidenced the sensitivity of H(2)L(ring) to the copper-mediated aerobic oxidation, which results in two derivatives of the ligand, a quinazoline and an amide. The quinazoline ligand is acting as monoanionic and mononucleating through its O,N,N binding site, while the amide ligand behaves as a trianionic and binucleating through its O,N,N,N and O,O binding sites in Cu(2)(L(amide))(L(quinazoline))(MeOH)·2MeOH.

Metal-assisted ring-closing/opening process of a chiral tetrahydroquinazoline.

The ring-chain tautomerism of a 2-aryl-1,2,3,4-tetrahydroquinazoline has been exploited to induce reversible changes in the aminal-imine equilibrium, as desired, by coordination of a suitable metal ion. This process was studied by NMR and UV-vis spectroscopies, X-ray crystallography, and molecular modeling approach. The results obtained show that the imine H(2)L(i) undergoes a selective ring-closing reaction upon complexation with Ni(2+). As a result, complexes of the type Ni(HL(a))(2) are obtained, whose chirality arises from the chiral ligand H(2)L(a) and the helicity of the structure. Hence, helical enantiomers form the following racemates: [Δ-C(R,R)N(S,S),Λ-C(S,S)N(R,R)]-Ni(HL(a))(2)·2HOAc and [Δ,Λ-C(S,R)N(R,S)]-Ni(HL(a))(2)·4MeOH. In contrast to the situation observed for Ni(2+), the cyclic tautomer of the ligand, H(2)L(a), undergoes a selective ring-opening reaction upon complex formation with Pd(2+), ultimately yielding Pd(HL(i))(2)·MeOH, in which the open-chain imine ligand is bidentate through the N,O donor set of the quinoline residue. Density functional theory calculations were conducted to provide insight into the different behavior of both coordinated metals (Ni(2+) and Pd(2+)) and to propose a mechanism for the metal-assisted opening/closing reaction of the tetrahydroquinazoline ring.